FIG 3.
Regulation of bacterial adhesion by host cytoskeleton. (A) Actin rearranges around attached bacteria. After static incubation with E. coli VHH (orange), HeLa cells displaying GFP with a CD80 anchor (green) were stained for actin (purple). Bar, 5 μm. (B) Bacteria promote actin embeddings in the absence of any cytosolic component in the mammalian cell. After static coculture with E. coli VHH (red), HeLa cells displaying GFP with a glycosylphosphatidylinositol (GPI), which does not harbor any cytosolic signaling domain, also show strong actin remodeling around attached bacteria. (C) HeLa cell treatment with the actin polymerization inhibitor cytochalasin D (cytoD) reduces the bacterial count per HeLa cell. (D) Bacterial contact efficiency is independent of actin polymerization. (E) The characteristic residence time τres decreases in the presence of cytochalasin D at high VHH density. Statistical tests: two-way ANOVA and Sidak post hoc test (****, P < 10−4; **, P < 0.01; ns, not significant).